Gravity-type pipe conveyance systems for waste or storm water generally include a mainline pipe or conduit to which service lateral pipes are connected. Many applications call for the connection of the lateral pipes to be made such that the lateral is perpendicular to the mainline pipe. Such connections are often referred to as “Tee” connections or service connections. Alternatively, the service lateral pipe can be connected at an angle (although with the long axis intersecting the long axis of the mainline pipe) and is thus designated, for example, as a “Wye” or 45-Degree service connection.
Service connections require a hole to be cored through the sidewall of the mainline pipe. The diameter of the cored hole is made slightly larger than the diameter of the service lateral pipe, which has a smaller diameter than the mainline pipe.
One effective service connection system is available from Inserta Fittings Inc., the assignee of the present application (www.insertatee.com) and marketed under the trademark INSERTA FITTINGS. That system comprises a three-piece service connection that is compression fit, without special tooling, into the hole that is cored through the wall of a wastewater or storm water mainline pipe. The three-piece service connection consists of a substantially rigid, cylindrical, hollow hub, one end of which fits into an elastomeric sleeve. The sleeved hub end is compression fit into the cored hole in the mainline pipe. A stainless steel band is fastened around the sleeve to secure it to the hub. The exposed end of the hub defines a conventional bell component of a bell and spigot joint, and receives the spigot end of the service lateral that is to be connected. This type of service connection may be used with any of a wide variety of pipe types (concrete, PVC, corrugated, etc).
In some instances the cored hole in the mainline pipe is not properly formed. As a result, the central axis of the hole does not intersect the long axis of the mainline pipe. Consequently, the misaligned hole made in the sidewall of the mainline pipe will be oblong rather than circular. This may result in attendant misalignment of the service connection with the mainline pipe, hence misalignment of the service lateral.
It is also possible for an installer to apply excessive axial force on the service lateral pipe when fitting the spigot end of that pipe into the connection hub. In such an instance, and especially where the cored hole is not quite circular, the excessive force may cause an undesirable amount of penetration of the sleeved end of the hub into the mainline pipe, which can result in interference with the operation and/or inspection of the mainline pipe.
The present invention is directed to an improved lateral pipe connection assembly that effects proper alignment of the lateral connection and restricts to the desired amount the penetration of the hub into the cored hole of the mainline pipe.